Suction accumulator for refrigeration systems



May 19, 1970 DrR. GRAHL SUCTION ACCUMULATOR FOR REFRIGERATION SYSTEMS Filed May 5. 1968 Darwin R. Grahl, Novelty, Ohio, assignor to Parker- HannifinCorporation, Cleveland, Ohio, a corporation of Ohio FiledMay 3, 1968, Ser. No. 726,363

Int. Cl. F25b 43/00 US. Cl. 62-503 3 Claims ABSTRACT OF THE DISCLOSURE A suction accumulator for a refrigeration system with means to prevent delivery of liquid to the compressor intake. The accumulator comprises a tank having an inlet at its bottom for receiving refrigerant fluid in vaporized form but which may include slugs of liquid, and has an outlet at its upper end for delivering the vapor to a compressor, and there being a straight tube in the tank with an open end to receive the, vapor at the tank inlet and having a closed 'end and a transverse opening near the tank outlet whereby any slugs of liquid in the tube are prevented by the closed end from reaching the tank outlet and are diverted through the. transverse openings so as to drop to the tank bottom.

BACKGROUND OF THE INVENTION Suction accumulators are used in refrigeration systems to receive vaporized refrigeration fluid from the system for .recirculation by the compressor. The fluid coming into the accumulator may be only partially vaporized and thus be partially in liquid form. Also, condensation of the vapor occurs within the. tank during periods that the system is not in operation and likewise occurs to some extent during operation. In addition, it is desirable that oil be circulated with the refrigerant fluid for lubricating the compressor and other moving parts in the system. Thus, oil as well as refrigerant fluid is likely to be present in liquid form in the tank at all times.

It is important that the accumulator deliver fluid only in vapor form to the compressor because intake of liquid therein would quickly cause extensive damage to the cornpressor.

SUMMARY OF THE INVENTION The invention assures that only saturated vapor is delivered to the compressor and it aids in vaporizing fluid that is in liquid form. These objectives are accomplished by providing centered coaxial inlet and outlet openings respectively at the bottom and top of a cylindrical tank for connection to the evaporator discharge and compressor intake and by providing a straight tube within the tank to receive the incoming fluid. The tube extends from the inlet opening toward the outlet but the upper end of the tube is closed and there are one or more transverse openings near the upper end whereby vapor and liquid moving upwardly within the tube discharges through the transverse openings and into the tank in a direction away from the outlet. The discharging liquid impinges against the cylindrical side wall of the tank, which is hot during normal operation, and thus aids in promoting vaporization. Any liquid not vaporized at this time falls by gravity to the bottom of the tank and only saturated vapor is discharged from the tank outlet. Because the tube is centered in the cylindrical tank liquid passing through any transverse opening travels the same lateral distance to impinge upon the tank wall and thus provides for maximum vaporation. The coaxial alignment of the tube with the outlet opening provides maximum assurance that liquid United States. Patent ice.

will not discharge from the tube transverse openings to the outlet.

The tube includes a metering orifice near the bottom of the tank. When the system is not in operation liquid within the tank enters the tube through the orifice and fills the tube to the level of liquid within the tank. Upon startup, the liquid withinthe tube is forced rapidly u-pward by pressure differential but the closed end of the tube causes it to discharge sidewardly from the tube and fall to the tank bottom, as already described. During operation, liquid oil enters the tube through the orifice at a metered or restricted rate and is mixed with the refrigerant vapor for discharge to the compressor.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a vertical cross section view of the accumulator tank and shows the tube partly in elevation and partly in cross section.

DESCRIPTION OF THE INVENTION In the illustrated embodiment, the accumulator includes a cylindrical tank 10 with a rounded top and bottom and with an outlet opening 11 at the top into which a tube 12 leading to the intake side of a compressor (not shown) is sealingly mounted by brazing or other means.

It its lower end the tank has an inlet opening 15 in which a tube 16 is likewise sealingly mounted by brazing or the like. Tube 16 projects from outlet 15 and is brazed to another tube 17 coming from the evaporator. Tube 16 is straight and projects toward outlet 11 and in axial alignment therewith. The upper end 18 of the tube is closed by any suitable means, as for example by pinching, capping, or spinning and brazing, and is spaced a short distance from outlet 11. Spaced downwardly a short distance from closed end 18 are one or more transverse openings 19. Near the bottom of tank 10 tube 16 has a restrictor orifice 21.

OPERATION When the refrigeration system is not in operation, the tank will contain some liquid 22 at its lower end which may be oil alone or a mixture of oil and liquid refrigerant fluid. The liquid will have entered tube 16 through orifice 21 so that it will have filled the tube to a level equal to that of the liquid in the tank. The remainder of the tank and tube space will be filled with refrigerant fluid vapor.

Upon starting the system, the compressor will start drawing vapor from the tank through outlet 11 and tube 12 and reduce the pressure in the vapor space so that liquid within tube 16 will rapidly rise therein. Closed end 18 of the tube will prevent the rising liquid from discharging into tube 12 and cause such liquid to discharge laterally from tube 16 through transverse openings 19. As the liquid discharges from openings 19 it impinges upon the side wall of tank 10 and drops to the tank bottom. Thus no liquid is discharged into conduit 12.

As the refrigeration system continues in operation and the liquid initially within tube 16 is either vaporized or returned to the tank through openings 19, additional liquid is metered into the tube through orifice 21. This additional liquid vaporizes within the tube and mixes with the refrigerant vapor entering through conduit 17 for discharge to conduit 12.

As operation of the system continues, the refrigerant fluid entering tube 16 from conduit 17 is normally in vaporized form but occasionally may include some liquid. In the latter case, the liquid moves upwardly in the tube and because of closed end 18 is discharged laterally through transverse opening 19 against the cylindrical wall of the tank. Some of this liquid will vaporize, either within tube 16 or tank 10, and be discharged into tube 12 or it will remain in liquid form and drop to the bottom 2; The accumulator of claim 1 in which the top end of of tank 10 after passing through openings 19. the cylindrical tank is rounded and said closed upper end I claim: is radially opposite at least a portion of said rounded end. 1. A suction accumulator for a refrigeration system 3. The accumulator of claim 1 in which said transverse comprising a cylindrical tank having a side Wall and hav- 5 opening is spaced from said closed end. ing axial aligned outlet and inlet openings at its top and bottom respectively, a straight tube extending through the References Cited inlet opening into the tank and having a closed upper end UNITED STATES PATENTS near the outlet opening, said tube having a transverse opening at said upper end, the axis of said transverse open- 10 2 323 ing being substantially normal to the axis of the tube 3009335 11/1961 klsing 62:503

whereby fluid entering the tube at said inlet passes through the transverse opening and is directed toward said side MEYER PERLIN, Primary Examiner Wall, and said tube having an aperture therein below said transverse opening communicating the interior of the tube 15 US. Cl. X.R. with the interior of the tank. 62--471 

